Hammer



HAMME R Filed Nov. 23, 1937 rgggtk 14 21 INVENTORS J. F. HEM/\TT BY J- H HOERSTER ATTORNEY.

Patented Apr. 5, 1938 UNITED STATES HAMMER.

John. F. Hewitt and John1H..:Hoerster, POrtland,

.Oreg.

Application November 23, 1937, Serial No. 176,024

5 Claims.

This invention relates generally to tools, and particularly to a hammer.

The main object of this invention is the construction of a mechanically driven hammer whose 5 operation may be easily controlled in a manner that the blow struck thereby may range from alight tap to a blow of considerable'force.

The second object is to so construct the hammer that its parts will be simple to manufacture and will not require extreme accuracy in. its production.

The third object is the construction of a hammer of the class described which will lend itself to use where compressed air is not available.

The fourth object is the construction of a mechanical hammer which may be operated by a rotating flexible shaft.

These and other objects are accomplished in the manner set forth in the following specification as illustrated in the accompanying drawing,

in which:

Fig. 1 is a perspective view of the device.

Fig. 2 is a section taken along the line 22 in Fig. 1.

Fig. 3 is a section taken along the line 3-3 in Fig. 2.

Fig. 4 is a section taken along the lineT4-4 in Fig; 2.

Fig. 5 is an end elevation of the eccentric shaft and drive shaft showing the parts in a driving position.

Fig. 6 is a view similar to Fig. 5 but showing the parts in a neutral position.

Fig. '7 is a side elevation of the plunger.

Fig. 8 is a section taken along the line 88 in Fig. 2.

Similar nmnerals refer to similar parts throughout the several Views.

Referring in detail to the drawing, there is shown the tubular head It] having a side outlet ll upon which is mounted a tubular handle l2. Mounted in the ends of the head In are the bushings l3 on the outer side of which are placed the grease retainers l4. Extending through the bushings l3 and grease retainers I4 is a cylindrical plunger [5 having formed on one side thereof a flat area l6 through which is formed the slot I! which is inclined with relation to the longitudinal axis of the plunger I5. The opposite ends of the plunger l5 are provided with the chambers l8 and I 9, each of which is provided with a recess 20.

In this case we have illustrated a single tool 2| having a work engaging head 22 which may be of any desired shape. The tool 2| is provided with the spring urged plungers '23 which are adapted to engage the recess 20. On the end of the handle I2 is disposed an anti-friction bearing 24 in which journals the drive shaft 25.

The shaft 25 has an enlarged end 26 which journals in the bronze bushing 21. In the enlarged portion of the drive shaft 25 is formed a cylindrical opening 28 adapted to receive the enlarged portion 29 of the eccentricshaft 30. v

Theshaftjfl hasfformed on one end thereof an. eccentric pin 3| which extends into the slot 'llrvof the plunger'l5 while the end 32 of the drive shaft 251s close to the flattened face l6 of the plunger "[5.

Slidably disposed on the drive shaft 25 is a collar'33 which is drivablyconnected to the shaft I25by'n'1eans of the spline'34. On the'drive shaft 25'is secured the'flanged collar 35 "by means of the set screws 36. A spring 31 is placed 'around the shaft'25 between the collars 35 and 33 for the purpose of urging same apart. The drive shaft 25'is provided with a cut-away portion 38, which communicates with the cylindrical opening 39 in which journals the eccentric shaft 30. A tangent pin '40 extends through the collar 33 .andinto the eccentric shaft 30 which shaft has "formed therein a spiral groove 4| adapted to permit the collar "33 to move longitudinally and thereby rotating theeccentric shaft 30. A thrust bearing 42 is placed against the end of the collar'33.

A sleeve 43 is slidably mounted on the shaft 25. The sleeve 43 has formed on one end thereof a flange 44 which engages the thrust bearing 42. The sleeve 43 is preferably non-rotatable and has its sides 45 flattened to receive the arms 46 of a forked lever 41 which is pivoted on the pin 48 and is operated by means of a hand lever 49. The arms 46 engage the flange 44.

The shaft 25 is provided with a tapped hole 50 to receive the end of the flexible drive shaft 5| which maybe rotated by any convenient source of power.

The operation of the device is as follows:

When rotary motion is supplied to the shaft 25 by means of the flexible drive shaft 5|, it causes the eccentric shaft 30 to revolve about the axis of the shaft 25 which coincides with the axis of the pin 3| when the device is in a neutral position, in which event the pin. 3| merely rotates within the slot ll. However, when the lever 49 is moved toward the handle [2, the arms 46 move to compress the spring 31 by sliding the collar 33 along the shaft 25. This movement causes the pin 40 to move along the groove 4i and rotate the eccentric shaft 30 on its axis causing the pin 3| to assume a position which is eccentric with relation to the shaft 25, and since the pin 3| is rotated with the shaft 25, the result is a reciprocating movement at the plunger l5.

Obviously, the more the hand lever 49 is moved toward the handle l2, the greater will be the degree of eccentricity and the greater will be the force of the blow struck by the hammer head 22.

It must be understood that while the present drawing illustrates a desired form of this invention, it is not intended that the claims shall be limited to the precise form shown, it being intended to cover all forms and modifications of this invention which fall fairly within the appended claims.

We claim:

1. A mechanically driven hammer having a slidable tool holding plunger. having a slot formed in the side thereof, a handle for supporting said plunger, a drive shaft mounted in said handle, an eccentric shaft eccentrically mounted in said handle in a manner that a portion thereof may be moved to and from a concentric position, said portion occupying said slot and means for controlling the degree of eccentricity of said slot occupying portion.

2. The device of the class described having in combination a head, a plunger slidably mounted in said head, a handle attached to said head, a drive shaft rotatably mounted in said handle, said drive shaft having an opening formed therein parallel with its axis and spaced therefrom, an eccentric shaft having a portion thereof occupying said opening and having an eccentric portion projecting beyond the end of said drive shaft into said plunger, said plunger having a transverse slot formed therein adapted to receive said eccentric portion, a spring urged collar mounted on said drive shaft, a tangent pin mounted in said collar, said eccentric shaft having a spiral groove therein into which said pin projects and means for moving said collar longitudinally along said drive shaft for the purpose of rotating said eccentric shaft and varying the degree of eccentricity of the end thereof.

3. In a device of the class described, the combination of a head having a handle on the side thereof and having a plunger slidably mounted therein normal to said handle, a drive shaft mounted in said handle having an eccentric shaft eccentrically mounted therein so that a portion of said eccentric shaft may be rotated to a concentric position with relation to said drive shaft, said eccentric shaft having a spiral groove formed therein, a collar on said drive shaft having a tangent pin therein adapted to engage said groove, a spring in said handle adapted to urge said collar in a direction which will move a portion of said eccentric shaft to a concentric position, an anti-friction bearing engaging said collar, a flanged sleeve engaging said bearing, a forked lever engaging the flange of said sleeve, means for actuating said lever in a manner to compress said spring and a plunger in said head having a slot formed therein adapted to receive said eccentric shaft end, said slot being characterized by being inclined with relation to the axis of said plunger.

4. In a hammer of the class described, a slidable tool holding plunger having a slot formed across one side thereof, said slot being inclined with relation to tile direction of movement of said plunger, an eccentric shaft having one portion thereof projecting into said slot and having the second portion thereof rotatably mounted within a drive shaft, said second portion being eccentric with relation to said drive shaft, means for varying the relation between the positions of said drive shaft and eccentric shaft and means for rotating said drive shaft.

5. An eccentric drive for mechanical hammers consisting of a drive shaft having an eccentric shaft eccentrically mounted therein, said eccentric shaft having projecting from the end thereof and in eccentric relation thereto a pin which may assume a position concentric with relation to said drive shaft or eccentric with relation thereto, together with a cylindrical plunger having a flattened side adjacent to said drive shaft, said plunger having a slot formed in said flattened side inclined with relation to its axis, said slot being adapted to receive said pin, said plunger being reciprocated by the rotation of said drive shaft to a distance corresponding with twice the distance between the neutral position of said drive shaft and the eccentric position thereof.

JOHN F. HEWITT. JOHN H. HOERSTER. 

